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page ,132 title COMMAND - resident code for COMMAND.COM name COMMAND;/*; * Microsoft Confidential; * Copyright (C) Microsoft Corporation 1991; * All Rights Reserved.; */
;*****************************************************************************;; MODULE: COMMAND.COM;; DESCRIPTIVE NAME: Default DOS command interpreter;; FUNCTION: This version of COMMAND is divided into three distinct; parts. First is the resident portion, which includes; handlers for interrupts 23H (Cntrl-C), 24H (fatal; error), and 2EH (command line execute); it also has; code to test and, if necessary, reload the transient; portion. Following the resident is the init code, which; is overwritten after use. Then comes the transient; portion, which includes all command processing (whether; internal or external). The transient portion loads at; the end of physical memory, and it may be overlayed by; programs that need as much memory as possible. When the; resident portion of command regains control from a user; program, a check sum is performed on the transient; portion to see if it must be reloaded. Thus programs; which do not need maximum memory will save the time; required to reload COMMAND when they terminate.;; ENTRY POINT: PROGSTART;; INPUT: command line at offset 81H;; EXIT_NORMAL: No exit from root level command processor. Can exit; from a secondary command processor via the EXIT; internal command.;; EXIT_ERROR: Exit to prior command processor if possible, otherwise; hang the system.;; INTERNAL REFERENCES:;; ROUTINES: See the COMMAND Subroutine Description Document; (COMMAND.DOC);; DATA AREAS: See the COMMAND Subroutine Description Document; (COMMAND.DOC);; EXTERNAL REFERENCES:;; ROUTINES: none;; DATA AREAS: none;;*****************************************************************************;; REVISION HISTORY; ----------------;; DOS 1.00 to DOS 3.30; --------------------------; SEE REVISION LOG IN COPY.ASM ALSO;; REV 1.17; 05/19/82 Fixed bug in BADEXE error (relocation error must return to; resident since the EXELOAD may have overwritten the transient.;; REV 1.18; 05/21/82 IBM version always looks on drive A; MSVER always looks on default drive;; REV 1.19; 06/03/82 Drive spec now entered in command line; 06/07/82 Added VER command (print DOS version number) and VOL command; (print volume label);; REV 1.20; 06/09/82 Prints "directory" after directories; 06/13/82 MKDIR, CHDIR, PWD, RMDIR added;; REV 1.50; Some code for new 2.0 DOS, sort of HACKey. Not enough time to; do it right.;; REV 1.70; EXEC used to fork off new processes;; REV 1.80; C switch for single command execution;; REV 1.90; Batch uses XENIX;; Rev 2.00; Lots of neato stuff; IBM 2.00 level;; Rev 2.01; 'D' switch for date time suppression;; Rev 2.02; Default userpath is NUL rather than BIN; same as IBM; COMMAND split into pieces;; Rev 2.10; INTERNATIONAL SUPPORT;; Rev 2.50; all the 2.x new stuff -MU;; Rev 3.30 (Ellen G); CALL internal command (TBATCH2.ASM); CHCP internal command (TCMD2B.ASM); INT 24H support of abort, retry, ignore, and fail prompt; @ sign suppression of batch file line; Replaceable environment value support in batch files; INT 2FH calls for APPEND; Lots of PTR fixes!;; Beyond 3.30 to forever (Ellen G); ----------------------;; A000 DOS 4.00 - Use SYSPARSE for internal commands; Use Message Retriever services; /MSG switch for resident extended error msg; Convert to new capitalization support; Better error recovery on CHCP command; Code page file tag support; TRUENAME internal command; Extended screen line support; /P switch on DEL/ERASE command; Improved file redirection error recovery; (removed) Improved batch file performance; Unconditional DBCS support; Volume serial number support; (removed) COMMENT=?? support;; A001 PTM P20 Move system_cpage from TDATA to TSPC;; A002 PTM P74 Fix PRESCAN so that redirection symbols do not; require delimiters.;; A003 PTM P5,P9,P111 Included in A000 development;; A004 PTM P86 Fix IF command to turn off piping before; executing;; A005 DCR D17 If user specifies an extension on the command; line search for that extension only.;; A006 DCR D15 New message for MkDir - "Directory already; exists";; A007 DCR D2 Change CTTY so that a write is done before XDUP;; A008 PTM P182 Change COPY to set default if invalid function; returned from code page call.;; A009 PTM P179 Add CRLF to invalid disk change message;; A010 DCR D43 Allow APPEND to do a far call to SYSPARSE in; transient COMMAND.;; A011 DCR D130 Change redirection to overwrite an EOF mark; before appending to a file.;; A012 PTM P189 Fix redirection error recovery.;; A013 PTM P330 Change date format;; A014 PTM P455 Fix echo parsing;; A015 PTM P517 Fix DIR problem with * vs *.;; A016 PTM P354 Fix extended error message addressing;; A017 PTM P448 Fix appending to 0 length files;; A018 PTM P566,P3903 Fix parse error messages to print out parameter; the parser fails on. Fail on duplicate switches.;; A019 PTM P542 Fix device name to be printed correctly during; critical error;; A020 DCR D43 Set append state off while in DIR;; A021 PTM P709 Fix CTTY printing ascii characters.;; A022 DCR D209 Enhanced error recovery;; A023 PTM P911 Fix ANSI.SYS IOCTL structure.;; A024 PTM P899 Fix EXTOPEN open modes.;; A025 PTM P922 Fix messages and optimize PARSE switches;; A026 DCR D191 Change redirection error recovery support.;; A027 PTM P991 Fix so that KAUTOBAT & AUTOEXEC are terminated; with a carriage return.;; A028 PTM P1076 Print a blank line before printing invalid; date and invalid time messages.;; A029 PTM P1084 Eliminate calls to parse_check_eol in DATE; and TIME.;; A030 DCR D201 New extended attribute format.;; A031 PTM P1149 Fix DATE/TIME add blank before prompt.;; A032 PTM P931 Fix =ON, =OFF for BREAK, VERIFY, ECHO;; A033 PTM P1298 Fix problem with system crashes on ECHO >"";; A034 PTM P1387 Fix COPY D:fname+,, to work;; A035 PTM P1407 Fix so that >> (appending) to a device does; do a read to determine eof.;; A036 PTM P1406 Use 69h instead of 44h to get volume serial; so that ASSIGN works correctly.;; A037 PTM P1335 Fix COMMAND /C with FOR;; A038 PTM P1635 Fix COPY so that it doesn't accept /V /V;; A039 DCR D284 Change invalid code page tag from -1 to 0.;; A040 PTM P1787 Fix redirection to cause error when no file is; specified.;; A041 PTM P1705 Close redirected files after internal APPEND; executes.;; A042 PTM P1276 Fix problem of APPEND paths changes in batch; files causing loss of batch file.;; A043 PTM P2208 Make sure redirection is not set up twice for; CALL'ed batch files.;; A044 PTM P2315 Set switch on PARSE so that 0ah is not used; as an end of line character;; A045 PTM P2560 Make sure we don't lose parse, critical error,; and extended message pointers when we EXIT if; COMMAND /P is the top level process.;; A046 PTM P2690 Change COPY message "fn File not found" to; "File not found - fn";; A047 PTM P2819 Fix transient reload prompt message;; A048 PTM P2824 Fix COPY path to be upper cased. This was broken; when DBCS code was added.;; A049 PTM P2891 Fix PATH so that it doesn't accept extra characters; on line.;; A050 PTM P3030 Fix TYPE to work properly on files > 64K;; A051 PTM P3011 Fix DIR header to be compatible with prior releases.;; A052 PTM P3063,P3228 Fix COPY message for invalid filename on target.;; A053 PTM P2865 Fix DIR to work in 40 column mode.;; A054 PTM P3407 Code reduction and critical error on single line; PTM P3672 (Change to single parser exported under P3407);; A055 PTM P3282 Reset message service variables in INT 23h to fix; problems with breaking out of INT 24h;; A056 PTM P3389 Fix problem of environment overlaying transient.;; A057 PTM P3384 Fix COMMAND /C so that it works if there is no space; before the "string". EX: COMMAND /CDIR;; A058 PTM P3493 Fix DBCS so that CPARSE eats second character of; DBCS switch.;; A059 PTM P3394 Change the TIME command to right align the display of; the time.;; A060 PTM P3672 Code reduction - change PARSE and EXTENDED ERROR; messages to be disk based. Only keep them if /MSG; is used.;; A061 PTM P3928 Fix so that transient doesn't reload when breaking; out of internal commands, due to substitution blocks; not being reset.;; A062 PTM P4079 Fix segment override for fetching address of environment; of parent copy of COMMAND when no COMSPEC exists in; secondary copy of environment. Change default slash in; default comspec string to backslash.;; A063 PTM P4140 REDIRECTOR and IFSFUNC changed interface for getting; text for critical error messages.;; A064 PTM P4934 Multiplex number for ANSI.SYS changed due to conflict; 5/20/88 with Microsoft product already shipped.;; A065 PTM P4935 Multiplex number for SHELL changed due to conflict; 5/20/88 with Microsoft product already shipped.;; A066 PTM P4961 DIR /W /P scrolled first line off the screen in some; 5/24/88 cases; where the listing would barely fit without the; header and space remaining.;; A067 PTM P5011 For /E: values of 993 to 1024 the COMSPEC was getting; 6/6/88 trashed. Turns out that the SETBLOCK for the new; environment was putting a "Z block" marker in the old; environment. The fix is to move to the old environment; to the new environment before doing the SETBLOCK.;; A068 PTM P5568 IR79754 APPEND /x:on not working properly with DIR/VOL; 09/19/88 because the check for APPEND needed to be performed; before the DIR's findfirst.;; A069 PTM P5726 IR80540 COMSPEC_flag not properly initialized and; 10/30/88 executed. Causing AUSTIN problem testing LAN/DW4 re-; loading trans w/new comspec with no user change comspec.;; A070 PTM P5734 IR80484 Batch file causes sys workspace to be corrupted.; 11/05/88 Expansion of environment variables into batch line of; 128 chars was not being counted and "%" which should be; ignored were being counted.;; A071 PTM P5854 IR82061 Invalid COMMAND.COM when Word Perfect, Prompt; 03/02/89 used. Comspec_flag was not in protected data file be-; ing included in checksum and was being overwritten by; WP. Moved var from Tspc to Tdata so Trans would reload.; Also removed fix A069 (because flag now protected).;; C001 VERSION 4.1 Add new internal command - SERVICE - to display the DOS; 07/25/89 version and CSD version in U.S. date format. Files; changed - TRANMSG,.SKL,COMMAND1,TDATA,TCMD2A,USA.MSG;;***********************************************************************************
;; Revision History; ================;; M021 SR 08/23/90 Fixed Ctrl-C handler to handle Ctrl-C; at init time (date/time prompt);
.xcref.xlist include dossym.inc ; basic DOS symbol set include syscall.inc ; DOS function names include comsw.asm ; build version info include comequ.asm ; common command.com symbols include resmsg.equ ; resident message names
include comseg.asm ;segment ordering.list.cref
CODERES segment public byteCODERES ends
DATARES segment public byte extrn AccDen:byte extrn Batch:word extrn EchoFlag:byte extrn ExeBad:byte extrn ExecEMes:byte extrn ExecErrSubst:byte extrn ExtCom:byte extrn ForFlag:byte extrn IfFlag:byte extrn InitFlag:BYTE extrn Nest:word extrn PipeFlag:byte extrn RBadNam:byte extrn RetCode:word extrn SingleCom:word extrn TooBig:byte
extrn OldDS:word EXTRN SCS_REENTERED:BYTE EXTRN SCS_CMDPROMPT:BYTE
DATARES ends
INIT segment public para extrn ConProc:near extrn Init_Contc_SpecialCase:nearINIT ends
include envdata.asm
Prompt32 equ 1
;*** START OF RESIDENT PORTION
CODERES segment public byte
public Ext_Exec public ContC public Exec_Wait public Exec_Ret
assume cs:CODERES,ds:NOTHING,es:NOTHING,ss:NOTHING
extrn LodCom:near extrn LodCom1:near
org 0Zero = $
;; org 80h - 1;;ResCom label byte;; public ResCom
;; org 100h
public StartCodeStartCode:;; jmp RESGROUP:ConProc
;*** EXEC error handling;; COMMAND has issued an EXEC system call and it has returned an error.; We examine the error code and select an appropriate message.
; Bugbug: optimize reg usage in following code? Careful of DX!; Condense the error scan?; RBADNAM is checked by transient, no need here?; Move below Ext_Exec.
Exec_Err:;SR;; ds,es are setup when the transient jumps to Ext_Exec. So segment regs are;in order here
assume ds:DATARES,es:DATARES
; Bugbug: can we use byte compares here?; Might be able to use byte msg#s, too.
; Store errors in a 3 or 4 byte table. Msg #s in another.; Speed not high priority here.
; Move this to transient.
mov bx,offset DATARES:RBadNam cmp al,ERROR_FILE_NOT_FOUND je GotExecEMes ; bad command mov bx,offset DATARES:TooBig cmp al,ERROR_NOT_ENOUGH_MEMORY je GotExecEMes ; file not found mov bx,offset DATARES:ExeBad cmp al,ERROR_BAD_FORMAT je GotExecEMes ; bad exe file mov bx,offset DATARES:AccDen cmp al,ERROR_ACCESS_DENIED je GotExecEMes ; access denied
Default_Message: mov bx,offset DATARES:ExecEMes ; default message mov si,offset DATARES:ExecErrSubst ; get address of subst block
GotExecEMes: mov dx,bx ; DX = ptr to msg;; williamh: no reason of doing this. When command.com receives a command,;; it means the VDM process has been created successfully and there;; is no way for the parent process to know that we are not able;; to launch the program and therefore, it won't display any error;; message for us.;; cmp byte ptr [scs_reentered],1;; jne NoErrMsg;; cmp byte ptr [scs_cmdprompt],Prompt32;; je NoErrMsg invoke RPrintNoErrMsg: jmp short NoExec
;*** EXEC call;; The transient has set up everything for an EXEC system call.; For cleanliness, we issue the EXEC here in the resident ; so that we may be able to recover cleanly upon success.;; CS,DS,ES,SS = DATARES seg addr
Ext_Exec:;SR;; The words put on the stack by the stub will be popped off when we finally;jump to LodCom ( by LodCom).;;; int 21h ; do the exec
Exec_Ret: jc Exec_Err ; exec failed
; The exec has completed. Retrieve the exit code.
Exec_Wait: mov ah,WAITPROCESS ; get errorlevel int 21h ; get the return code mov RetCode,ax
; See if we can reload the transient. The external command; may have overwritten part of the transient.
NoExec:;SR;; ds = es = ss = DATARES when we jump to LodCom; jmp LodCom
;*** Int 23 (ctrl-c) handler;; This is the default system INT 23 handler. All processes; (including COMMAND) get it by default. There are some; games that are played: We ignore ^C during most of the; INIT code. This is because we may perform an ALLOC and; diddle the header! Also, if we are prompting for date/time; in the init code, we are to treat ^C as empty responses.
; Bugbug: put init ctrl-c handling in init module.
;SR;; The stub has pushed the previous ds and DATARES onto the stack. We get;both these values off the stack now;ContC proc far
assume cs:CODERES,ds:NOTHING,es:NOTHING,ss:NOTHING
pop ds ;ds = DATARES assume ds:DATARES; pop OldDS ;OldDS = old ds
test InitFlag,INITINIT ; in initialization? jz NotAtInit ; no test InitFlag,INITSPECIAL ; doing special stuff? jz CmdIRet ; no, ignore ^C pop ds ; restore before jumping; M021 jmp RESGROUP:Init_ContC_SpecialCase ; Yes, go handle itCmdIret:;SR;; Restore ds to its previous value;
; mov ds,OLdDS ; pop ds iret ; yes, ignore the ^C
NotAtInit: test InitFlag,INITCTRLC ; are we already in a ^C? jz NotInit ; nope too.
;* We are interrupting ourselves in this ^C handler. We need; to set carry and return to the user sans flags only if the; system call was a 1-12 one. Otherwise, we ignore the ^C.
cmp ah,1 jb CmdIRet cmp ah,12 ja CmdIRet
pop ds ;restore ds to old value add sp,6 ; remove int frame stc
; mov ds,OldDS ;restore ds to its old value ret 2 ; remove those flags...
NotInit:
;* We have now received a ^C for some process (maybe ourselves; but not at INIT).; ; Note that we are running on the user's stack!!! Bad news if; any of the system calls below go and issue another INT; 24... Massive stack overflow! Another bad point is that; SavHand will save an already saved handle, thus losing a; possible redirection...; ; All we need to do is set the flag to indicate nested ^C. ; The above code will correctly flag the ^C diring the; message output and prompting while ignoring the ^C the rest; of the time.; ; Clean up: flush disk. If we are in the middle of a batch; file, we ask if he wants to terminate it. If he does, then; we turn off all internal flags and let the DOS abort.
or InitFlag,INITCTRLC ; nested ^c is on sti
;; push cs ; el yucko! change the user's ds!!;; pop ds;; assume ds:RESGROUP
pop ax ;discard the old ds value
mov ax,SingleCom or ax,ax jnz NoReset push ax mov ah,DISK_RESET int 21h ; reset disks in case files were open pop ax
NoReset:
; In the generalized version of FOR, PIPE and BATCH, we would; walk the entire active list and free each segment. Here,; we just free the single batch segment.
test Batch,-1 jz ContCTerm or ax,ax jnz ContCTerm invoke SavHand invoke AskEnd ; ask if user wants to end batch
; If the carry flag is clear, we do NOT free up the batch file
jnc ContBatch mov cl,EchoFlag ; get current echo flag push bx
ClearBatch: mov es,Batch ; get batch segment mov di,BatFile ; get offset of batch file name; Bugbug: verify the following shell interface still works;; mov ax,MULT_SHELL_BRK ; does the SHELL want this terminated?;; int 2Fh ; call the SHELL;; cmp al,SHELL_ACTION ; does shell want this batch?;; je Shell_Bat_Cont ; yes - keep it
mov bx,es:BatForPtr ; get old FOR segment cmp bx,0 ; is a FOR in progress je no_bat_for ; no - don't deallocate push es ; mov es,bx ; yes - free it up... mov ah,DEALLOC ; int 21h ; pop es ; restore to batch segment
No_Bat_For: mov cl,es:BatEchoFlag ; get old echo flag mov bx,es:BatLast ; get old batch segment mov ah,DEALLOC ; free it up... int 21h mov Batch,bx ; get ready to deallocate next batch dec nest ; is there another batch file? jnz ClearBatch ; keep going until no batch file
; We are terminating a batch file; restore the echo status
Shell_Bat_Cont: ; continue batch for SHELL
pop bx mov EchoFlag,cl ; reset echo status mov PipeFlag,0 ; turn off pipeflagContBatch: invoke Crlf ; print out crlf before returning invoke RestHand
; Yes, we are terminating. Turn off flags and allow the DOS to abort.
ContCTerm: xor ax,ax ; indicate no read mov bp,ax
; The following resetting of the state flags is good for the; generalized batch processing.
mov IfFlag,al ; turn off iffing mov ForFlag,al ; turn off for processing call ResPipeOff cmp SingleCom,ax ; see if we need to set singlecom jz NoSetSing mov SingleCom,-1 ; cause termination on ; pipe, batch, forNoSetSing:
; If we are doing an internal command, go through the reload process.; If we are doing an external, let DOS abort the process.; In both cases, we are now done with the ^C processing.
and InitFlag,not INITCTRLC cmp ExtCom,al jnz DoDAb ; internal ^c jmp LodCom1DoDAb: stc ; tell dos to abort
;SR;;We dont need to restore ds here because we are forcing DOS to do an abort;by setting carry and leaving flags on the stack; ret ; Leave flags on stackContC endp
;SR;; ds = DATARES on entry. This routine is called from DskErr and LodCom1 and;both have ds = DATARES;
ResPipeOff: public ResPipeOff
assume ds:DATARES,es:NOTHING
savereg <ax> xor ax,ax xchg PipeFlag,al or al,al jz NoPipePop shr EchoFlag,1NoPipePop: restorereg <ax> return
CODERES ends end
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